Super Street Fighter II features re-done music for all of the returning characters, along with new tracks for the four new challengers. However, I think the re-done music sounds worse than before. I do like Cammy and Fei-Long's themes, though, and Vega's new ending theme is awesome. He and the other three boss characters now have their own ending themes rather than sharing the same one, as they have been for the last two games.

Character themes

Danger music
(Played in the second and third rounds of the fight, when one character has little vitality left)

Ending themes
The second part of Ken's ending STILL goes on for longer in the sound test than it does in the actual game, did the composer not get told how long Ken's ending was?

Other
The Tournament Champion and Tournament Vs. tracks are only used in Super Street Fighter II: The Tournament Battle.